Exercise. You don't have to be sedentary if you have asthma. Regular exercise can strengthen your heart and lungs, so they don't have to work so hard. It can also help you lose weight and lower your risk of developing other serious diseases, including cardiovascular disease and diabetes cardiovascular disease and diabetes . Aim for 30 minutes of exercise on most days. If you've been inactive, start slowly and try to increase your activity over time. Keep in mind that cold-weather exercises, such as skiing, are more likely to cause wheezing. If you do exercise in cold weather, wear a face mask to warm the air you breathe. And don't exercise if the temperature is below zero. Activities such as golf, walking and swimming are less likely to trigger attacks, but be sure to discuss any exercise program with your doctor.

Use your air conditioner. This helps reduce your exposure to airborne pollen from trees, grasses and weeds. Air conditioning also lowers indoor humidity and can reduce your exposure to dust mites. If you don't have air conditioning, try to keep your windows closed during pollen season.

Decontaminate your decor. To minimize dust that may aggravate nighttime symptoms, encase mattresses, pillows and box springs in dustproof covers that can be removed and cleaned frequently. Replace bedding made of down, kapok or foam rubber with synthetic materials such as Dacron. Wash sheets, pillowcases and mattress pads weekly in hot water. Replace synthetic pillows every 2 to 3 years.

Maintain optimal humidity. Keep humidity low (40 percent to 50 percent) in your home and office. If you live in a damp climate, talk to your doctor about using a dehumidifier.

Keep indoor air clean. Have a utility company check your air conditioner and furnace once a year. Change the filters in your furnace and air conditioner according to the manufacturer's instructions. Also consider installing a small-particle filter in your ventilation system. If you use a humidifier, change the water daily.

Reduce pet dander. If you're allergic to dander, avoid pets with fur or feathers. Having pets regularly bathed or groomed also may reduce the amount of dander in your surroundings.

Clean regularly. Clean your home at least once a week. Because cleaning stirs up dust, however, wear a mask or, if you can, have someone else clean.

Limit use of contacts. Try substituting eyeglasses for your contact lenses when the pollen count is high. Pollen grains can become trapped under the lenses.